This paper aims to predict the inelastic behavior of thin-walled steel and composite structures, such as hollow and concrete-filled steel columns. For this purpose, a three-dimensional (3D) elasto-plastic finite element analysis methodology has been presented for both thin-walled steel columns with pipe and box-shaped sections, and concrete-filled steel box columns. By comparing with experimental result, it is concluded that the proposed analytical method can give an accurate prediction to the experimental results of both steel and composite structures.